Slate grinding or dressing machine



(No Model.)

S. S. MARSHALL.

SLATB GRINDING 0R DRESSING MACHINE.

No. 878,587. Patented Jan. 17 1888.

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N Pimm Phmmhugmphqrl wzsmngmua f 'UNITED STATES i' PATENT OFFICE.

A SAMUEL s. MARSHALL, or sLAriNorroN, PENNSYLVANIA.

SLATE GRINDING OR DRESSING MACHINE.

SPECIFICATION forming part of Letters Patent No. 376,537, dated January 17, 1888.

Application filed January 4, 1887. Serial No. 223,386. (No model.)

To @ZZ whom it may concern:

Be it known that' I, SAMUEL S. MARSHALL, of Slatington, in the county of Lehigh and State of Pennsylvania, have invented a new and Improved Slate Grinding or Dressing Machine, of which the following is a full, clear, and exil act description.

The object of my invention is to provide a practical machinefor grinding school and other slates; and the invention consists of the construction, arrangement, and combination of parts, all as hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in both figures.

Figure 1 is a sectional plan view, and Fig. 2 is a sectional elevation, of the machine.

Arepresents the base of the frame of the machine, from which rise four posts or uprights,B, joined at their upper ends by the cross-pieces C D E. Journaled in the two outer posts, B, is the horizontal Shaft F, which communicates motion to a vertical shaft, G, by means ofthe pulleys H H and the belt H. Secured upon the vertical shaftG is the large wheel J, preferably of cast-iron. This wheel J has a flat grindingsurface,j, and has numerous passages, j'j', made through it for the passage of Sand and water admitted to the wheel from the tank K. A ange, b, is formed upon` or attached to the periphery ofthe wheel J, to prevent the sand and Water from being thrown oft' from the Wheel by centrifugal force, and channels c c are formed in the upper surface of the wheel for distributing the sand and water to the different passagesj. Beneath the wheel J are placed numerous hollow standards L, only two being shown in the drawings; but there may be as many as can be placed around the wheel, the number varying according to the size of slates intended to be ground. In each standard L is placed a vertically-movaable shaft or rod, L', to the upper end of which is attached a table, L2, and the rods L are adapted to be moved vertically by levers L3 for moving the tables L2 to and from the wheel J. The slates M to be ground are held upon removable plates N, each provided with a handle, N', the plates N being adapted to be placed upon the tables L2, as Shown in Fig. 2. The tables L2 are formed with slots Z and the platesN with lugs or ribs Z', to t insaid slots, so that they may be retained securely upon the tables against the friction of the wheel, and also moved back and forth radially to the wheel J by the handles N, and pins or other holding devices 'Z are fitted in the plates N for holding the pieces of slate M Securely upon the plates.

In operation the wheel J is set in motion, sand and water admitted from the tank K, and the plates N, with slates M, are placed upon the tables L2, which are raised by levers L3 to hold the slates in contact with the wheel. The plates N are then reciprocatcd slowly by the handles N', which movement increases the grinding action of the wheel J, andthe pressure may be increased or diminished, as required, for the best result.

By constructing the machine in the manner described the slates are not .only rapidly reduced, but many can be ground at the same time by the same wheel, there being an attendant for each slate-support around the wheel.

Having thus described my invention,what I claim as new, and desire to secure by Letters Patent, is

l. The grinding-wheel J, formed with a peripheral ange, b, and formed with the passages j', and the vertically-movable rods L beneath the wheel J, provided with the supports or tables L2 at their upper ends, in combination with the plates N, held upon the tables L2 in guides radial to the wheel J, substantially as described.

2. The con1bination,with the grinding-wheel J, therods L' and L3, for lifting the same, and the tables L2, held upon the Said :rods and formed with slots Z, of the plates N, formed with handles N', and with the ribs Z', to enter the slots Z, substantially as described.

SAMUEL S. MARSHALL. 

